/Engine/Source/Editor/UMGEditor/Public/Templates/WidgetTemplateClass.h
Called when objects need to be swapped out for new versions, like after a blueprint recompile.
void OnObjectsReplaced ( const [TMap](API\Runtime\Core\Containers\TMap)< [UObject](API\Runtime\CoreUObject\UObject\UObject) *, [UObject](API\Runtime\CoreUObject\UObject\UObject) * > & ReplacementMap )